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Ylikoski J, Markkanen M, Pirvola U, Lehtimäki JA, Ylikoski M, Jing Z, Sinkkonen ST, Mäkitie A. Stress and Tinnitus; Transcutaneous Auricular Vagal Nerve Stimulation Attenuates Tinnitus-Triggered Stress Reaction. Front Psychol 2020; 11:570196. [PMID: 33041937 PMCID: PMC7527536 DOI: 10.3389/fpsyg.2020.570196] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 08/26/2020] [Indexed: 01/22/2023] Open
Abstract
Introduction Tinnitus can become a strong stressor for some individuals, leading to imbalance of the autonomous nervous system with reduction of parasympathetic activity. It can manifest itself as sleep disturbances, anxiety and even depression. This condition can be reversed by bioelectrical vagal nerve stimulation (VNS). Conventional invasive VNS is an approved treatment for epilepsy and depression. Transcutaneous VNS (taVNS) stimulating the auricular branch of the vagus nerve has been shown to activate the vagal pathways similarly as an implanted VNS. Therefore, taVNS might also be a therapeutic alternative in health conditions such as tinnitus-related mental stress (TRMS). This retrospective study in 171 TRMS patients reports the clinical features, psychophysiological characteristics, and results of the heart rate variability (HRV) tests before and after test-taVNS. This study also reports the therapy outcomes of 113 TRMS patients treated with taVNS, in combination with standard tinnitus therapy. Methods Diagnostic tinnitus and hearing profiles were defined. To detect possible cardiac adverse effects, test-taVNS with heart rate monitoring as well as pre- and post-stimulation HRV tests were performed. Daily taVNS home therapy was prescribed thereafter. To assess therapeutic usefulness of taVNS, 1-year follow-up outcome was studied. Results of HRV tests were retrospectively analyzed and correlated to diagnostic data. Results The large majority of patients with TRMS suffer from associated symptoms such as sleep disturbances and anxiety. Baseline HRV data showed that more than three quarters of the 171 patients had increased sympathetic activity before test-taVNS. Test-taVNS shifted mean values of different HRV parameters toward increased parasympathetic activity in about 80% of patients. Test-taVNS did not cause any cardiac or other side effects. No significant adverse effects were reported in follow-up questionnaires. Conclusion TRMS is an example of a stress condition in which patients may benefit from taVNS. As revealed by HRV, test-taVNS improved parasympathetic function, most efficiently in patients with a low starting HRV level. Our tinnitus treatment program, including taVNS, effectively alleviated tinnitus stress and handicap. For wider clinical use, there is a great need for more knowledge about the optimal methodology and parameters of taVNS.
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Silvola JT, Sinkkonen ST, Wanscher J, Westman E, Holm NH, Ovesen T. The status of Eustachian tube balloon dilations in Nordic countries. World J Otorhinolaryngol Head Neck Surg 2019; 5:148-151. [PMID: 31750427 PMCID: PMC6849347 DOI: 10.1016/j.wjorl.2019.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 09/22/2019] [Indexed: 11/09/2022] Open
Abstract
There is no unanimous consensus for indications of eustachian tube balloon dilation (ETBD). Nordic countries have relatively similar hospital organizations and treatment guidelines. Therefore, it was logical to organize a consensus meeting of ETBD. The symposium: Nordic Experiences on Eustachian Tube Balloon Dilation, in Copenhagen, 30–31 March, 2017. The panellists from Denmark, Finland, Norway and Sweden and the attendees of the meeting agreed a consensus on the following issues: Candidates, Definition of Eustachian Tube Dysfunction, Diagnostic Work up, Differential Diagnosis, Contraindications, ETBD Procedure, Complications, Follow-up, and Outcomes. The article also presents the status for ETBD in each of these countries. Thereafter the consensus statement has been discussed in the national societies and meetings for ear surgeons in each of these countries. It can be assumed that surgeons in the hospitals of these Nordic countries generally follow the recommendations from the consensus meeting.
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Tötterman M, Jukarainen S, Sinkkonen ST, Klockars T. A Comparison of Four Digital Otoscopes in a Teleconsultation Setting. Laryngoscope 2019; 130:1572-1576. [PMID: 31670399 DOI: 10.1002/lary.28340] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/15/2019] [Accepted: 09/12/2019] [Indexed: 12/25/2022]
Abstract
OBJECTIVES/HYPOTHESIS This study compares image quality and appropriateness for teleconsultations for three different otological conditions. STUDY DESIGN Web-based survey. METHODS We compared four digital otoscopes via a Web-based questionnaire distributed to all Finnish ear, nose, and throat (ENT) specialists and residents. The survey consisted of three fictional patient cases, each of which was presented with images taken using the otoscopes studied. Respondents assessed the image quality on a visual analog scale (VAS), assessing its appropriateness for teleconsultations and comparing images taken using different otoscopes to one another. RESULTS In total, 98 individuals responded, consisting of 81 ENT specialists and 17 ENT residents. The CellScope Oto and Digital MacroView received higher VAS scores for image quality and appropriateness for teleconsultations than the FireFly and Delfino otoscopes (P < .001 for all comparisons). Respondents considered the CellScope Oto more appropriate for teleconsultations for exostoses than the three other otoscopes. The CellScope Oto and Digital MacroView were equally appropriate in the two other cases (normal ear and perforated tympanic membrane). CONCLUSIONS Both digital otoscopes and the underlying otological conditions affect the appropriateness of teleconsultations. Moreover, both factors should be considered when evaluating the suitability of otologic teleconsultations. Among the otoscopes evaluated, images taken using the CellScope Oto received the best overall assessments. LEVEL OF EVIDENCE NA Laryngoscope, 130:1572-1576, 2020.
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Luukkainen V, Kivekäs I, Silvola J, Jero J, Sinkkonen ST. Balloon Eustachian Tuboplasty: Systematic Review of Long-term Outcomes and Proposed Indications. J Int Adv Otol 2019; 14:112-126. [PMID: 29764785 DOI: 10.5152/iao.2018.4769] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Balloon Eustachian tuboplasty (BET) aims to improve the function of the Eustachian tube (ET). The objective of this study was to review the long-term outcome of BET and present the process and results of outlining indications for BET by the Finnish Otosurgical Society. The literature review is based on a database search performed in May 2017. The search resulted in 100 individual articles, which were screened for relevance. Five articles fulfilled the inclusion criteria (follow-up ≥12 months). Five additional articles (follow-up, 6-11 months) were analyzed to obtain supportive information. The proposed BET indications were constituted in the 2016 annual meeting of the Finnish Otosurgical Society. The workshop included a review of the Eustachian tube physiology, middle ear aeration mechanisms, and BET outcome studies. Thereafter, the members of the Society first voted and then discussed 14 cases in order to conclude whether BET was indicated in each case, and subsequently, a consensus statement on the indications for BET was outlined. The long-term follow-up studies were heterogeneous regarding the Eustachian tube dysfunction (ETD) definition, patient selection, follow-up duration, additional treatments, and outcome measures. The current, but limited, evidence suggests that BET is effective in the long-term. However, more long-term studies with uniform criteria and outcome measures as well as placebo-controlled studies are needed. The proposed indications for BET by the Finnish Otosurgical Society include chronic bothersome symptoms referring to ETD, ETD-related symptoms when pressure changes rapidly, or recurring serous otitis media. With the current evidence, we suggest treating only adults with BET.
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Luukkainen V, Jero J, Sinkkonen ST. Balloon Eustachian tuboplasty under monitored anaesthesia care with different balloon dilation devices: A pilot feasibility study with 18 patients. Clin Otolaryngol 2018; 44:87-90. [PMID: 30281926 DOI: 10.1111/coa.13236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 09/02/2018] [Accepted: 09/23/2018] [Indexed: 11/30/2022]
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Lamminmäki S, Sinkkonen ST, Atula T. Multiple cranial nerve injuries and neck abscesses caused by a transorally penetrating organic stick. BMJ Case Rep 2018; 2018:bcr-2017-224021. [PMID: 30042100 PMCID: PMC6059225 DOI: 10.1136/bcr-2017-224021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Foreign bodies cause a remarkable number of otolaryngological emergency visits and occasionally result in life-threatening conditions and later-emerging complications. Patient recovery depends on the detection and proper extraction of all foreign materials. Despite various obtainable diagnostic tools, adequate anamnesis forms the basis of clinical reasoning and should direct later examinations and radiological imaging. This case report describes a challenging patient with a unique trauma mechanism: many pieces of a fragmented organic foreign body emerged within 1 year of the initial injury, leading to repeated operations, a long period in an intensive care unit and a long-term swallowing and speech dysfunction.
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Luukkainen V, Vnencak M, Aarnisalo AA, Jero J, Sinkkonen ST. Patient satisfaction in the long-term effects of Eustachian tube balloon dilation is encouraging. Acta Otolaryngol 2018; 138:122-127. [PMID: 29017385 DOI: 10.1080/00016489.2017.1384568] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECT To investigate the long-term effects of balloon Eustachian tuboplasty (BET) from patient's perspective and to discover which symptoms of Eustachian tube dysfunction (ETD) benefit the most from BET. METHOD We designed a retrospective postal questionnaire based on the seven-item ETD questionnaire (ETDQ-7). Our questionnaire covered the severity of present ETD symptoms in comparison with the preoperative situation, the severity of current overall ear symptoms, and possible surgical interventions after BET. Forty-six patients treated in our institution between 2011 and 2013 fulfilled the inclusion criteria and 74% (34 patients; total 52 ears treated with BET) returned the questionnaire with a mean follow-up time of 3.1 years (range 1.8-4.6 years). RESULTS Pain in the ears, feeling of pressure in the ears, and feeling that ears are clogged had reduced in 75% of the ears that suffered from these symptoms preoperatively. Seventy-seven percent of all the responders felt that their overall ear symptoms were reduced. Altogether, 82% of all the patients stated that they would undergo BET again if their ear symptoms returned to the preoperative level. CONCLUSION Patient satisfaction in the long-term effects of BET is encouraging. These results may help clinicians in preoperative patient selection and counselling.
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Luukkainen V, Kivekäs I, Hammarén-Malmi S, Rautiainen M, Pöyhönen L, Aarnisalo AA, Jero J, Sinkkonen ST. Balloon Eustachian tuboplasty under local anesthesia: Is it feasible? Laryngoscope 2017; 127:1021-1025. [PMID: 28409844 DOI: 10.1002/lary.26488] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 12/06/2016] [Accepted: 12/12/2016] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To study whether balloon Eustachian tuboplasty (BET) is a feasible and safe procedure under local anesthesia. STUDY DESIGN Prospective multicenter case-control study. METHODS Patients undergoing either BET (n = 13) or endoscopic sinus surgery (ESS) (n = 12) under local anesthesia, with the possibility of sedation and analgesia, were monitored during the procedure and recovery period for possible adverse effects. After the procedure, the patients responded to a questionnaire assessing their experience. RESULTS No adverse effects were detected in the BET group. Patients in the BET group reported similar Visual Analog Scale scores for pain during the operation as the ESS group (5.0 ± 0.7 vs. 3.2 ± 0.7, mean ± standard error of the mean). However, patients in the BET group experienced more discomfort (4.2 ± 0.6 vs. 2.5 ± 0.3, respectively, P = 0.049). Seventy-seven and 92% of the patients in the BET and ESS groups, respectively, considered the anesthesia and pain relief to be sufficient. Patients from both the BET and ESS groups were almost devoid of pain 1 to 2 hours postoperatively (0.8 ± 0.2 and 1.4 ± 0.3, respectively). In total, 12 of 13 patients in the BET group, and all 12 patients in the ESS group, would choose local anesthesia with sedation and analgesia if they needed to undergo the same procedure again. CONCLUSION BET is a safe and feasible procedure under monitored anesthesia care, including local anesthesia along with sedation and analgesia. There is need for further methodological improvement to reduce pain and discomfort during the operation. LEVEL OF EVIDENCE 4. Laryngoscope, 127:1021-1025, 2017.
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Pelkonen T, Sarajuuri A, Rautanen T, Sinkkonen ST, Jero J. Meningoencephalitis and otitis media in a child with Mycoplasma pneumoniaeinfection. ACTA OTO-LARYNGOLOGICA CASE REPORTS 2017. [DOI: 10.1080/23772484.2016.1247249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Nicoli TK, Sinkkonen ST, Anttila T, Mäkitie A, Jero J. Jugulotympanic paragangliomas in southern Finland: a 40-year experience suggests individualized surgical management. Eur Arch Otorhinolaryngol 2016; 274:389-397. [PMID: 27380272 DOI: 10.1007/s00405-016-4184-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 06/27/2016] [Indexed: 10/21/2022]
Abstract
Treatment of jugulotympanic paragangliomas (JTPGLs) remains challenging with no clear guidelines for management or follow-up. The aim of this retrospective case-note study was to assess long-term results of operatively and conservatively managed JTPGLs between years 1974-2013. A total of 36 patients with JTPGLs were identified. Clinical characteristics and management outcomes of patients were reviewed. Data were extracted on demographics, symptoms, timing of diagnosis, tumor location and size, embolization, and management, including pre- and post-operative imaging, analysis of operative techniques, and follow-up. Pulsatile tinnitus and hearing loss were the most common presenting symptoms. Thirty-four (94 %) patients were treated with primary surgical therapy and two (6 %) with radiotherapy. The surgical approaches included endaural approach for Fisch Class A tumors and a variety of approaches for Fisch Class B-D tumors with an increasing predilection for function-preserving surgery. Eight (24 %) patients received subtotal resection. Five (15 %) patients had a local recurrence within 10 years after primary surgery. Two (6 %) patients suffered a permanent cranial nerve (CN) deficit after primary surgery. We advocate radical surgery when tumor resection is possible without compromising CNs. Function-preserving surgery with at least a 10-year follow-up for Fisch Class B-D tumors should be considered if CNs are in danger.
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Atula S, Sinkkonen ST, Saat R, Sairanen T, Atula T. Association of multiple sclerosis and sudden sensorineural hearing loss. Mult Scler J Exp Transl Clin 2016; 2:2055217316652155. [PMID: 28607727 PMCID: PMC5433330 DOI: 10.1177/2055217316652155] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/08/2016] [Indexed: 11/25/2022] Open
Abstract
Background Multiple sclerosis (MS) may affect other cranial nerves besides the optic nerve. Sudden
sensorineural hearing loss (SSHL), possibly caused by a deficit in the auditory tract,
including the vestibulocochlear nerve, is sometimes associated with MS. Objectives We aimed to assess the incidence of SSHL among MS patients, its frequency as an initial
symptom of MS, and magnetic resonance imaging (MRI) findings associated with SSHL in
MS. Methods We collected retrospectively all patients diagnosed with MS and SSHL at the Helsinki
University Hospital between 2004 and 2014. Patients with both diagnoses were
re-evaluated using hospital medical records, audiograms and head MRI scans. Results A total of 2736 patients were diagnosed with MS, 1581 patients with SSHL, and 18
patients (0.7% of all MS patients) with both; two patients presented with SSHL as an
initial symptom of MS. The annual incidence of SSHL was 59.8/100 000 (95% confidence
interval (CI) 37.7–94.9) in MS patients, and 12.4/100 000 (95% CI 11.8–13.0) in the
normal population. Conclusion SSHL is a rare symptom of MS and is even less frequent as an initial symptom. Its
incidence in MS patients, however, markedly exceeds that in the normal population.
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Sinkkonen ST, Ruohoalho J, Pietarinen P, Aaltonen LM, Mäkitie AA, Bäck LJ. Limited long-term outcome of single-session soft palate interstitial radiofrequency surgery for habitual snoring in tertiary care academic referral centre: Our experience on 77 patients. Clin Otolaryngol 2016; 42:470-473. [PMID: 26865418 DOI: 10.1111/coa.12632] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/07/2016] [Indexed: 11/28/2022]
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Sinkkonen ST, Kronlund L, Hautamäki J, Jero J, Aarnisalo AA, Kentala E. Evaluation of Temporal Difference Limen in Preoperative Non-Invasive Ear Canal Audiometry as a Predictive Factor for Speech Perception after Cochlear Implantation. Audiol Res 2014; 4:91. [PMID: 26557351 PMCID: PMC4627137 DOI: 10.4081/audiores.2014.91] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 01/24/2014] [Accepted: 02/26/2014] [Indexed: 12/04/2022] Open
Abstract
The temporal difference limen (TDL) can be measured with noninvasive electrical ear canal stimulation. The objective of the study wa to determine the role of preoperative TDL measurements in predicting patients’ speech perception after cochlear implantation. We carried out a retrospective chart analysis of fifty-four cochlear implant (CI) patients with preoperative TDL and postoperative bisyllabic word recognition measurements in Helsinki University Central Hospital between March 1994 and March 2011. Our results show that there is no correlation between TDL and postoperative speech perception. However, patient’s advancing age correlates with longer TDL but not-directly with poorer speech perception. The results are in line with previous results concerning the lack of predictive value of preoperativ TDL measurements in CI patients.
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Sinkkonen ST, Hildén O, Hagström J, Leivo I, Bäck LJ, Mäkitie AA. Experience of head and neck extracranial schwannomas in a whole population-based single-center patient series. Eur Arch Otorhinolaryngol 2014; 271:3027-34. [DOI: 10.1007/s00405-013-2871-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 12/18/2013] [Indexed: 10/25/2022]
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Sinkkonen ST, Jero J, Aarnisalo AA. [Tympanic membrane perforation ]. DUODECIM; LAAKETIETEELLINEN AIKAKAUSKIRJA 2014; 130:810-818. [PMID: 24822331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Tympanic membrane perforation may be caused by, e.g., trauma or acute or chronic middle ear infection. Perforation causes conductive hearing loss. Since it predisposes to infections, it is important to keep the ear dry. In most cases traumatic perforations heal spontaneously. Perforations caused by acute middle ear infections are treated with antibiotics. Chronic perforation due to chronic middle ear infection or cholesteatoma will usually not heal without surgery. Most perforation cases can be taken care of in primary care. ENT consultation is needed when alarming signs, such as continuous pain, vertigo or facial paralysis exist, or if the perforation persists.
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Kajosaari L, Sinkkonen ST, Laulajainen-Hongisto A, Jero J. [Acute mastoiditis in children]. DUODECIM; LAAKETIETEELLINEN AIKAKAUSKIRJA 2014; 130:251-257. [PMID: 24660384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Acute mastoiditis in children develops when acute otitis media (AOM) spreads into the mastoid air cells inside the temporal bone. The diagnosis is based on clinical findings of AOM with simultaneous signs of infection in the mastoid area. The most common pathogen causing acute mastoiditis in children is Streptococcus pneumoniae. Intravenous antimicrobial medication, tympanostomy and microbial sample are the cornerstones of the treatment. If a complication of mastoiditis is suspected, imaging studies are needed, preferably with magnetic resonance imaging. The most common complication of acute mastoiditis is a subperiosteal abscess.
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Sinkkonen ST, Starlinger V, Galaiya DJ, Laske RD, Myllykangas S, Oshima K, Heller S. Serial analysis of gene expression in the chicken otocyst. J Assoc Res Otolaryngol 2011; 12:697-710. [PMID: 21853378 DOI: 10.1007/s10162-011-0286-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 08/02/2011] [Indexed: 10/17/2022] Open
Abstract
The inner ear arises from multipotent placodal precursors that are gradually committed to the otic fate and further differentiate into all inner ear cell types, with the exception of a few immigrating neural crest-derived cells. The otocyst plays a pivotal role during inner ear development: otic progenitor cells sub-compartmentalize into non-sensory and prosensory domains, giving rise to individual vestibular and auditory organs and their associated ganglia. The genes and pathways underlying this progressive subdivision and differentiation process are not entirely known. The goal of this study was to identify a comprehensive set of genes expressed in the chicken otocyst using the serial analysis of gene expression (SAGE) method. Our analysis revealed several hundred transcriptional regulators, potential signaling proteins, and receptors. We identified a substantial collection of genes that were previously known in the context of inner ear development, but we also found many new candidate genes, such as SOX4, SOX5, SOX7, SOX8, SOX11, and SOX18, which previously were not known to be expressed in the developing inner ear. Despite its limitation of not being all-inclusive, the generated otocyst SAGE library is a practical bioinformatics tool to study otocyst gene expression and to identify candidate genes for developmental studies.
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Sinkkonen ST, Chai R, Jan TA, Hartman BH, Laske RD, Gahlen F, Sinkkonen W, Cheng AG, Oshima K, Heller S. Intrinsic regenerative potential of murine cochlear supporting cells. Sci Rep 2011; 1:26. [PMID: 22355545 PMCID: PMC3216513 DOI: 10.1038/srep00026] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 06/17/2011] [Indexed: 12/17/2022] Open
Abstract
The lack of cochlear regenerative potential is the main cause for the permanence of hearing loss. Albeit quiescent in vivo, dissociated non-sensory cells from the neonatal cochlea proliferate and show ability to generate hair cell-like cells in vitro. Only a few non-sensory cell-derived colonies, however, give rise to hair cell-like cells, suggesting that sensory progenitor cells are a subpopulation of proliferating non-sensory cells. Here we purify from the neonatal mouse cochlea four different non-sensory cell populations by fluorescence-activated cell sorting (FACS). All four populations displayed proliferative potential, but only lesser epithelial ridge and supporting cells robustly gave rise to hair cell marker-positive cells. These results suggest that cochlear supporting cells and cells of the lesser epithelial ridge show robust potential to de-differentiate into prosensory cells that proliferate and undergo differentiation in similar fashion to native prosensory cells of the developing inner ear.
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Hellsten KS, Sinkkonen ST, Hyde TM, Kleinman JE, Särkioja T, Maksimow A, Uusi-Oukari M, Korpi ER. Human locus coeruleus neurons express the GABA(A) receptor gamma2 subunit gene and produce benzodiazepine binding. Neurosci Lett 2010; 477:77-81. [PMID: 20417252 DOI: 10.1016/j.neulet.2010.04.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 03/30/2010] [Accepted: 04/19/2010] [Indexed: 01/23/2023]
Abstract
Noradrenergic neurons of the locus coeruleus project throughout the cerebral cortex and multiple subcortical structures. Alterations in the locus coeruleus firing are associated with vigilance states and with fear and anxiety disorders. Brain ionotropic type A receptors for gamma-aminobutyric acid (GABA) serve as targets for anxiolytic and sedative drugs, and play an essential regulatory role in the locus coeruleus. GABA(A) receptors are composed of a variable array of subunits forming heteropentameric chloride channels with different pharmacological properties. The gamma2 subunit is essential for the formation of the binding site for benzodiazepines, allosteric modulators of GABA(A) receptors that are clinically often used as sedatives/hypnotics and anxiolytics. There are contradictory reports in regard to the gamma2 subunit's expression and participation in the functional GABA(A) receptors in the mammalian locus coeruleus. We report here that the gamma2 subunit is transcribed and participates in the assembly of functional GABA(A) receptors in the tyrosine hydroxylase-positive neuromelanin-containing neurons within postmortem human locus coeruleus as demonstrated by in situ hybridization with specific gamma2 subunit oligonucleotides and autoradiographic assay for flumazenil-sensitive [(3)H]Ro 15-4513 binding to benzodiazepine sites. These sites were also sensitive to the alpha1 subunit-preferring agonist zolpidem. Our data suggest a species difference in the expression profiles of the alpha1 and gamma2 subunits in the locus coeruleus, with the sedation-related benzodiazepine sites being more important in man than rodents. This may explain the repeated failures in the transition of novel drugs with a promising neuropharmacological profile in rodents to human clinical usage, due to intolerable sedative effects.
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Bäck LJJ, Liukko T, Sinkkonen ST, Ylikoski J, Mäkitie AA. Complication rates of radiofrequency surgery in the upper airways: a single institution experience. Acta Otolaryngol 2009; 129:1469-73. [PMID: 19922099 DOI: 10.3109/00016480802706719] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSION Radiofrequency (RF) surgery of the upper airways appears to be a safe procedure with an acceptable incidence of minor and moderate complications. OBJECTIVES RF surgery is increasingly used in the treatment of patients with sleep disordered breathing and inferior turbinate hypertrophy. Our aim was to investigate the incidence and the severity of the complications of RF surgery in the upper airways. PATIENTS AND METHODS This was a retrospective, observational study at a tertiary care centre, academic teaching hospital during 1 year. Data from medical records were collected on 753 consecutive patients treated with RF surgery of the inferior turbinate, soft palate and base of the tongue. Patients with synchronous surgical treatment were excluded. RESULTS In all, 413 patients (66.3% males) with a mean age of 44.7 years (range 8-83 years) were treated with 2926 RF surgery ablations in 524 treatment sessions. There were no severe complications. The overall incidence of minor and moderate complications was low, i.e. 2.7% (11/524) and 0.6% (3/524) of the treatment sessions, and 0.5% (11/2926) and 0.1% (3/2926) of the ablations, respectively.
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Halonen LM, Sinkkonen ST, Chandra D, Homanics GE, Korpi ER. Brain regional distribution of GABA(A) receptors exhibiting atypical GABA agonism: roles of receptor subunits. Neurochem Int 2009; 55:389-96. [PMID: 19397945 DOI: 10.1016/j.neuint.2009.04.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Accepted: 04/17/2009] [Indexed: 11/19/2022]
Abstract
The major inhibitory neurotransmitter in the brain, gamma-aminobutyric acid (GABA), has only partial efficacy at certain subtypes of GABA(A) receptors. To characterize these minor receptor populations in rat and mouse brains, we used autoradiographic imaging of t-butylbicyclophosphoro[(35)S]thionate ([(35)S]TBPS) binding to GABA(A) receptors in brain sections and compared the displacing capacities of 10mM GABA and 1mM 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP), a competitive GABA-site agonist. Brains from GABA(A) receptor alpha1, alpha4, delta, and alpha4+delta subunit knockout (KO) mouse lines were used to understand the contribution of these particular receptor subunits to "GABA-insensitive" (GIS) [(35)S]TBPS binding. THIP displaced more [(35)S]TBPS binding than GABA in several brain regions, indicating that THIP also inhibited GIS-binding. In these regions, GABA prevented the effect of THIP on GIS-binding. GIS-binding was increased in the cerebellar granule cell layer of delta KO and alpha4+delta KO mice, being only slightly diminished in that of alpha1 KO mice. In the thalamus and some other forebrain regions of wild-type mice, a significant amount of GIS-binding was detected. This GIS-binding was higher in alpha4 KO mice. However, it was fully abolished in alpha1 KO mice, indicating that the alpha1 subunit was obligatory for the GIS-binding in the forebrain. Our results suggest that native GABA(A) receptors in brain sections showing reduced displacing capacity of [(35)S]TBPS binding by GABA (partial agonism) minimally require the assembly of alpha1 and beta subunits in the forebrain and of alpha6 and beta subunits in the cerebellar granule cell layer. These receptors may function as extrasynaptic GABA(A) receptors.
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Saarelainen KS, Ranna M, Rabe H, Sinkkonen ST, Möykkynen T, Uusi-Oukari M, Linden AM, Lüddens H, Korpi ER. Enhanced behavioral sensitivity to the competitive GABA agonist, gaboxadol, in transgenic mice over-expressing hippocampal extrasynaptic alpha6beta GABA(A) receptors. J Neurochem 2007; 105:338-50. [PMID: 18021290 DOI: 10.1111/j.1471-4159.2007.05136.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The behavioral and functional significance of the extrasynaptic inhibitory GABA(A) receptors in the brain is still poorly known. We used a transgenic mouse line expressing the GABA(A) receptor alpha6 subunit gene in the forebrain under the Thy-1.2 promoter (Thy1alpha6) mice ectopically expressing alpha6 subunits especially in the hippocampus to study how extrasynaptically enriched alphabeta(gamma2)-type receptors alter animal behavior and receptor responses. In these mice extrasynaptic alpha6beta receptors make up about 10% of the hippocampal GABA(A) receptors resulting in imbalance between synaptic and extrasynaptic inhibition. The synthetic GABA-site competitive agonist gaboxadol (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol; 3 mg/kg) induced remarkable anxiolytic-like response in the light : dark exploration and elevated plus-maze tests in Thy1alpha6 mice, while being almost inactive in wild-type mice. The transgenic mice also lost quicker and for longer time their righting reflex after 25 mg/kg gaboxadol than wild-type mice. In hippocampal sections of Thy1alpha6 mice, the alpha6beta receptors could be visualized autoradiographically by interactions between gaboxadol and GABA via [(35)S]TBPS binding to the GABA(A) receptor ionophore. Gaboxadol inhibition of the binding could be partially prevented by GABA. Electrophysiology of recombinant GABA(A) receptors revealed that GABA was a partial agonist at alpha6beta3 and alpha6beta3delta receptors, but a full agonist at alpha6beta3gamma2 receptors when compared with gaboxadol. The results suggest strong behavioral effects via selective pharmacological activation of enriched extrasynaptic alphabeta GABA(A) receptors, and the mouse model represents an example of the functional consequences of altered balance between extrasynaptic and synaptic inhibition.
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Möykkynen TP, Sinkkonen ST, Korpi ER. Compensation by reduced L-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor responses in a mouse model with reduced γ-aminobutyric acid type A receptor-mediated synaptic inhibition. J Neurosci Res 2007; 85:668-72. [PMID: 17131399 DOI: 10.1002/jnr.21138] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
L-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonists increase the threshold for electroshock-induced convulsions. Here, we show that a transgenic mouse line overexpressing cerebellum-restricted gamma-aminobutyric acid type A (GABA(A)) receptor alpha6 subunit in the hippocampal CA1 pyramidal cells (Thy1alpha6 mouse line) exhibits about a 20% increase in the electroshock current intensity inducing tonic hindlimb extension convulsion in 50% of the mice compared with that of their wild-type controls. AMPA receptor-mediated miniature excitatory postsynaptic currents (mEPSCs) in patch clamp recordings of CA1 pyramidal neurons in hippocampal slices had decreased amplitudes (8.4 +/- 2.2 pA) in the transgenics compared with the wild types (10.3 +/- 2.5 pA) but showed no change in current decay or frequency. Our results suggest that decreased AMPA-mediated neurotransmission might explain the increased threshold for electroconvulsions and warrant further studies on the regulation between various components of inhibition and excitation in neurons.
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Sinkkonen ST, Rabe H, Lüddens H, Korpi ER. Evidence for a reduction of coupling between GABAA receptor agonist and ionophore binding sites by inorganic phosphate. Neurochem Res 2006; 30:1471-82. [PMID: 16362766 DOI: 10.1007/s11064-005-8824-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/17/2005] [Indexed: 11/29/2022]
Abstract
[35S]TBPS binding to the GABAA receptor ionophore binding site is anion dependent. Using autoradiography on rat brain sections, we show that permeabilities of anions through the receptor channel correlate with their efficiencies to promote basal [35S]TBPS binding. Phosphate made an exception as it induced more binding than expected from its permeability. Well-permeable anions (chloride, nitrate, formate) allowed [35S]TBPS binding to be effectively displaced by 1 mM GABA, whereas low-permeable anions (acetate, phosphate, propionate) markedly prevented this GABA effect, especially in the thalamus, the transition from the high to the low GABA effect being between formate and acetate. In the presence of phosphate, GABA enhanced [3H]flunitrazepam binding to benzodiazepine site of recombinant alpha1beta2gamma2 receptors with the same efficacy but lower potency as compared to the presence of chloride, whereas [35S]TBPS binding was abnormally modulated by GABA. These results suggest that inorganic phosphate affects coupling between agonist and ionophore sites in GABAA receptors.
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Ranna M, Sinkkonen ST, Möykkynen T, Uusi-Oukari M, Korpi ER. Impact of epsilon and theta subunits on pharmacological properties of alpha3beta1 GABAA receptors expressed in Xenopus oocytes. BMC Pharmacol 2006; 6:1. [PMID: 16412217 PMCID: PMC1363348 DOI: 10.1186/1471-2210-6-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Accepted: 01/13/2006] [Indexed: 11/29/2022] Open
Abstract
Background γ-Aminobutyric acid type A (GABAA) receptors provide the main inhibitory control in the brain. Their heterogeneity may make it possible to precisely target drug effects to selected neuronal populations. In situ hybridization using rat brain sections has revealed a unique expression of GABAA receptor ε and θ subunit transcripts in the locus coeruleus, where they are accompanied at least by α3, α2, β1 and β3 subunits. Here, we studied the pharmacology of the human α3β1, α3β1ε, α3β1θ and α3β1εθ receptor subtypes expressed in Xenopus oocytes and compared them with the γ2 subunit-containing receptors. Results The GABA sensitivites and effects of several positive modulators of GABAA receptors were studied in the absence and the presence of EC25 GABA using the two-electrode voltage-clamp method. We found 100-fold differences in GABA sensitivity between the receptors, α3β1ε subtype being the most sensitive and α3β1γ2 the least sensitive. Also gaboxadol dose-response curves followed the same sensitivity rank order, with EC50 values being 72 and 411 μM for α3β1ε and α3β1γ2 subtypes, respectively. In the presence of EC25 GABA, introduction of the ε subunit to the receptor complex resulted in diminished modulatory effects by etomidate, propofol, pregnanolone and flurazepam, but not by pentobarbital. Furthermore, the α3β1ε subtype displayed picrotoxin-sensitive spontaneous activity. The θ subunit-containing receptors were efficiently potentiated by the anesthetic etomidate, suggesting that θ subunit could bring the properties of β2 or β3 subunits to the receptor complex. Conclusion The ε and θ subunits bring additional features to α3β1 GABAA receptors. These receptor subtypes may constitute as novel drug targets in selected brain regions, e.g., in the brainstem locus coeruleus nuclei.
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